After initializing the VPG, all writes to the protected virtual machines are sent by the VRA on the relevant host for each virtual machine on the protected site to the VRA on the recovery site specified as the recovery host for the virtual machine. The information is saved in the journal for the virtual machine with a timestamp, ensuring write-fidelity. Every few seconds the Zerto Virtual Manager writes a checkpoint to every journal on the recovery site for every virtual machine in the VPG, ensuring crash-consistency.

The data remains in the journal for the time defined by the journal history configuration, after which it is moved to the relevant mirror disks for each virtual machine. Both the journal and the mirror disks are managed by the VRA. In this way, you can recover the virtual machines using the mirror disks and the data in the journal. Refer to The Role of the Journal During Protection for more details about the journal.